TRANSACTIONS OF SECTION A. 583 



8. Report of the Committee on the Volcanic and Seismological Phenomena 

 of Jajjan. — See Reports, p. 123. 



9. On Phenomena which might he Ohservahle if the Hi/pothesis that Earth- 

 quakes are connected with Electrical Phenomena be entertained. By 

 Professor John Milne, F.B.S. 



It seems reasonable to assume that superheated high pressure steam escaping' 

 at a volcanic focus A through fissures to a region B — A and B heing more or less 

 insulated by partially non-conducting material — might also result in the develop- 

 ment of large quantities of electricity, followed ultimately by violent discharges. 



If a conductor C electrically connected vfith the surface, say the ocean, is 

 separated from B by partially non-conducting matter I, then BIO ruay be regarded 

 as a condenser, and the charges at B and are intensified. Discharges might also 

 take place between B and C, and the charges at A, B and C woidd act inductively 

 at the points «, b, c, of the surface respectively nearest to them. 



The phenomena related to the above hypothesis are as follows : — 



1. Earthquakes and Earth-currents. — -From a comparison of observations at 

 700 stations in Japan, there seems to be no connection between earthquakes and 

 abnormal disturbances on land lines. It would, however, seem that any subterra- 

 nean discharge — as, for instance, between A and B —must produce simultaneous 

 change of potential at a and b, and that therefore no change of current should be 

 expected. Thus the hypothesis is not opposed to the facts. 



2. Connection be.tiveen Earthqualies and Yolcanoes. — Most earthquakes do not 

 originate at volcanoes, but below the sea or on the coast-line where flat ground 

 suddenly slopes down below a deep ocean. From the hypothesis we should expect 

 that the greatest electric stress, and therefore the greatest disruptive stress, would 

 be between B and 0. 



3. Potential at Hot Springs. — Measurements made at seven springs in the 

 same valley extending from Yumoto, 100 to 200 feet above sea-level, to Ashiuoyu 

 3,000 feet above sea-level. Between a hot spring and the earth, 10 to 100 yards 

 distant, the diiTerence at the foot of the valley is about -05 of a volt, but at high 

 elevations, where the water is most sulphurous, the difference rose to 0'6 volt. 



The difference of potential between b and a neighbouring point ought to 

 increase when 6 is a volcanic vent. The existence of sulphurous water, however, 

 is not to be overlooked. 



4. Variations in Potential betioeen Water-Bearing Strata and the Superin- 

 cumbent Surface. — For more than 100 days a continuous photographic record was 

 taken of the difierence of the potentials of the water in a well 30 feet deep, and of 

 a point on the surface of the earth 25 yards off. At the time of three small earth- 

 quakes deflections equivalent to 2 or volts were observed, but they may have 

 been due to mechanical disturbance. 



10. Experimental Study of a Curious Movement of Ovoids and Ellipsoids. 

 By Professor Leconte. 



11. On Voivel Sounds. By Dr. R. J. Lr.ovD. — See p. 796. 



12. A Latent Characteristic of Aluminium- By Dr. A. Springee. 



According to the author's investigations aluminium is remarkably adapted for 

 use in the construction of sound-boards by possessing an elasticity capable of 

 sympathetic vibration uniformly through a wide range of tone-pitch, and by the 

 absence of higher partial tones during vibration. 



